2013

Sorption recovery of rare and rare earth metals from the multicomponent solutions of eudialite leach by the method of Acid Retardation in the columns with two liquid phases.

 Gruzdeva A.N., Zaitsev V.A., Krachak A.N., Khamizov R.Kh., Kogarko L.N.

Vernadsky Institute for geochemistry and analytical chemistry

Eudialite (Na₄(Ca,Ce)₂ (Fe,Mn,Y)(Zr,Nb)₂ [Si₃O₉] [Si₉(O,OH)₂₇] Cl) is perspective sourse of zirconium and rare earth elements. Lovosero massif contains huge volume of these rocks, with the eudialite as a rock-forming mineral. Existing technologies include acid decomposition of eudialite, and recovery process of rare metals from leach liquor which includes the stage of free acid neutralization. One of the main economic problems of these methods is high consumption of acid.

Method of Acid Retardation, based on the effect separation of aqueous mixtures of strong acids and their salts in the ion exchange column is a possible way for metal separation from acidic solutions [1]. The main drawback of this method is the degradation of concentration profiles due to pore filtration of liquid in sorbent bed. In GEOKHI RAS a modified sorption method of "Acid Retardation" and fundamentally-new way of mass-exchange processes organizing in the columns with two liquid phases was developed: the interspace volume in column is filled with organic liquid immiscible with water and filtrating aqueous solution [2, 3].

We experimentally studied separation of solution, formed by eudialite concentrate decomposition by HNO₃. Solution is pumped through the column which contains AB-17 anion-exchanger in NO₃^--form and decanole. The most part of cautions, including Na, Ca, Sr, Fe, Mn, Ti, Zr and Y are passing the chromatographic column immediately. Free acid is eluated to a high degree from the anion-exchanger afterwards just by the use of water. Ce and La sorption is much stronger than other metals, they concentration fronts are wider. The behavior of Nd is intermediate this two groups.

Our experiments show that modified method of Acid Retardation in sorption columns with two liquid phases may be used for separation of eudialite leach liquor into low-acid solution, enriched by Na, Ca, Sr, Fe, Mn, Ti, Zr, Y and heavy REE and Ce, La-rich acid, which can be used for decomposition of new portion of eudialite. 

This work was financially supported by RFBR RAS

1. M. J. Hatch , J. A. Dillon Acid Retardation. Simple Physical Method for Separation of Strong Acids from Their Salts// Eng. Chem. Process Des. Dev., 1963, 2 (4), pp 253–263

2. A.N. Krachak, R.Kh. Khamizov, V.A. Poznukhova, E.B. Podgornaya, V.A. Durnaykin Basic regularities of electrolyte separation in the method of Acid Retardation. I. Influence of cation type on the sorption of acids and their salts from binary solutions- Sorb. chromatogr. processes, 2011, т.11, №1.- с.77-88

3. R.Kh. Khamizov, A.N. Krachak, E.B. Podgornaya, S.Kh. Khamizov  Method and apparatus for conducting mass transfer processes EP2581134 A1 31/05/2011.